Spectacles which are foldable, not only by its side pieces but also around a hinge arranged between the lenses, have been around for a while. By folding the spectacles in different ways the size of the spectacles may be reduced and the fragile lenses may be protected from external forces while they are not used.
An example of such spectacles is disclosed in WO2010/022900A1 showing foldable spectacles with a folding mechanism between the two lenses which makes it possible to fold the lenses inwards, so that they may be protected by the side pieces when the spectacles are not used. Moreover, the side pieces are arranged in a telescopic manner which allows the spectacles to have a reduced size when folded. However, this known structure is not rigid in an unfolded state, i.e. when a user is using them, which means that the spectacles will not retain its shape. The known spectacles, when in a folded state, are not safely secured which means that parts of the spectacles may fall out or open up and therefor no longer be protected from external forces.
Another problem of prior-art spectacles, which is also valid for the spectacles previously described, is that they are only designed for a specific head size, as the side pieces are attached at a fixed distance from each other.
Further background art is reflected in US2010/0053546 which discloses eyeglass side pieces with flexible corrugations. A problem with these corrugations is that even though they may flex the side pieces in two directions, they are only adapted to adjust to a head size larger than the width between the side pieces. Another problem is that when the side pieces flex outwards parts of the same may create an undesired contact with the user's head.
Yet another example is disclosed in US2012/0224136 where a pair of foldable spectacles is shown and where the lenses in a folded state may be protected by portions of the spectacles. However, when the spectacles are in its folded state they are not safely secured which means that the spectacles may open or parts may fall out which may damage the lenses.
The foldable reading glasses disclosed in US2009/0190088 suffer from similar problems. Further background art is disclosed in U.S. Pat. No. 6,048,062 and U.S. Pat. No. 4,720,186.